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Titre : Troposphere modeling and filtering for precise GPS leveling Type de document : Thèse/HDR Auteurs : Frank Kleijer, Auteur Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 2004 Collection : Netherlands Geodetic Commission Publications on Geodesy, ISSN 0165-1706 num. 56 Importance : 262 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-90-6132-284-9 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Rayonnement électromagnétique
[Termes IGN] correction troposphérique
[Termes IGN] filtre de Kalman
[Termes IGN] modèle stochastique
[Termes IGN] nivellement par GPS
[Termes IGN] positionnement par GNSS
[Termes IGN] propagation troposphérique
[Termes IGN] simulation
[Termes IGN] traitement de données GNSS
[Termes IGN] troposphèreIndex. décimale : 24.30 Rayonnement électromagnétique Résumé : (Auteur) Precision : In the Netherlands, a precision of 5 rnm for estimated GPS height differ ences is required to achieve comparable accuracy as geoid height differences. This precision can be achieved for 24-hour data sets when applying a proper modeling. Precise levelling with GPS requires a judicious modeling of tropospheric delays, which has physical, functional, and stochastic aspect.
Modeling aspects : The physical modeling comprises zenith delays for the hydrostatic and wet component and zenith angle dependent mapping functions. Because the amount of water vapor in the atmosphere fluctuates widely and because the water-vapor aspect induced signal delays affect the height component strongly, a-priori modeling of these delays results in an insufficient precision of height differences. Parameterizing the tropospheric delay in the functional model is therefore necessary, at least for medium and long baselines. The observation model can further be strengthened by pseudo-observations. These pseudo-observations may be spatiotemporal constraints on tropospheric delay differences, or constraints on residual slant delays. With the latter type of constraint the isotropy assumption is loosened. An existing theoretical model is revised to obtain the corresponding covariance matrix. The stochastic modeling of both types of constraints is based on the assumption of Kohnogorov turbulence.
Filtering : The observation models can be implemented in a recursive filter like the Kalman Filter or the SRIF Several variations of these filters are described. For fast computations the most suitable recursive filtering technique is the Kalman-Cholesky Filter with pre-elimination of temporal GPS parameters, such as clock errors and ionospheric delays. Some tests and reliability descriptions are worked out for this filter. For practical implementation the temporal behavior of the zenith wet delay is to be assumed a random-walk process, which gives a fair description. The zenith wet delay can be estimated every epoch or every pre-defined batch of epochs.
Impact of model components : The effect of several model components on mainly the height is analyzed by simulation software. Special attention is given to the residual-slant-delay model because it is potentially precision and reliability improving. The impact of this model does however depend on the precision level of the observations and it still needs to be validated. Although observations to low-elevation satellites have a large contribution to the precision of the height, the residual-slant-delay model implies a strong down weighting of observations to satellites below ten degrees elevation. The highest accuracy can be obtained when the phase ambiguities are fixed. Even for long observation time spans this makes a difference of up effect on the formal precision of the height, but they have, a large influence on the precision of the filtered zenith delays. Because overconstraining (with constraints that are too tight) can have a large precision-deteriorating effect, spat iotemporal constraints are not recommended for GPS leveling. Further, short batches are preferred to avoid biases. To prevent the presence of near rank deficiencies, the zenith delays of one station are often fixed. From a precision point of view this is not necessary and is not recommended because this can also introduce biases. Even larger biases can be introduced when the zenith delays of all stations are fixed to their a-priori values. For very short baselines (< ±1 kin), this model is however justifiable because the formal precision improves considerately, keeping the effect of the biases in balance. to 15-20%. Batch size and spatiotemporal constraints turned out to have little effect on the formal precision of the height, but they have, a large influence on the precision of the filtered zenith delays. Because overconstraining (with constraints that are too tight) can have a large precision-deteriorating effect, spat iotemporal constraints are not recommended for GPS leveling. Further, short batches are preferred to avoid biases. To prevent the presence of near rank deficiencies, the zenith delays of one station are often fixed. From a precision point of view this is not necessary and is not recommended because this can also introduce biases. Even larger biases can be introduced when the zenith delays of all stations are fixed to their a-priori values. For very short baselines (< ±1 kin), this model is however justifiable because the formal precision improves considerately, keeping the effect of the biases in balance.Note de contenu : General introduction
I) Troposphere delay modeling for space geodetic measurements
Symbols and units in Part I
3 Introduction to Part I
4 Physics of the atmosphere
5 Zenith-delay models
6 Slant-delay models
7 Azimuthal asymmetry and gradient parameters
8 Conclusions of Part 1
A Temperature lapse rate
B Saastamoinen integrals
C Effective height
Bibliography
II) Paramerization of the tropospheric delay in GPS observation models
Symbols of Part II
9 Introduction to Part II
10 GPS observation equations
11 Eliminating rank deficiencies in troposphere-fixed models
12 Troposphere-float and weighted models
13 Near rank deficiencies
14 Pre-elimination transformations
15 Conclusions of Part II
III) Stochastic modeling of (slant) tropospheric delays observed by GPS
Symbols of Part III
16 Introduction to Part III
17 Power-law processes
18 Stochastic modeling of troposphere constraints
19 Conclusions of Part III
IV) Recursive GPS data processing
Symbols of Part IV
20 Introduction to Part IV
21 Kalman filtering with pre-elimination
22 Pre-elimination in a recursive SRIF
23 Implementation aspects
24 Condition equations, testing, and reliability
25 Conclusions of Part IV
V) Simulations
Symbols of Part V
26 Introduction to Part V
27 Software implementation
28 Means of quality assessment
29 Simulation scenarios
30 The troposphere-fixed model
31 Conclusions of Part V
32 Conclusions and recommendationsNuméro de notice : 16056 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère En ligne : https://ncgeo.nl/downloads/56Kleijer.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55149 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 16056-01 30.64 Livre Centre de documentation Géodésie Disponible 16056-02 24.30 Livre Centre de documentation Physique Disponible Documents numériques
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Troposphere modeling and filteringAdobe Acrobat PDFIntercalibration of vegetation indices from different sensor systems / M.D. Steven in Remote sensing of environment, vol 88 n° 4 (30/12/2003)
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Titre : Intercalibration of vegetation indices from different sensor systems Type de document : Article/Communication Auteurs : M.D. Steven, Auteur ; T.J. Malthus, Auteur ; F. Baret, Auteur ; H. Xu, Auteur ; M. Chopping, Auteur Année de publication : 2003 Article en page(s) : pp 412 - 422 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] données multicapteurs
[Termes IGN] indice de végétation
[Termes IGN] luminance lumineuse
[Termes IGN] réflectance végétale
[Termes IGN] simulation d'étalonnageRésumé : (Auteur) Spectroradiometric measurements were made over a range of crop canopy densities, soil backgrounds and foliage colour. The reflected spectral radiances were convoluted with the spectral response functions of a range of satellite instruments to simulate their responses. When Normalised Difference Vegetation Indices (NDVI) from the different instruments were compared, they varied by a few percent, but the values were strongly linearly related, allowing vegetation indices from one instrument to be intercalibrated against another. A table of conversion coefficents is presented for AVHRR, ATSR2, Landsat MSS, TM and ETM+, SPOT-2 and SPOT-4 HRV, IRS, IKONOS, SEAWIFS, MISR, MODIS, POLDER, Quickbird and MERIS (see Appendix A for glossary of acronyms). The same set of coefficients was found to apply, within the margin of error of the analysis, for the Soil Adjusted Vegetation Index SAVI. The relationships for SPOT vs. TM and for ATSR-2 vs. AVHRR were directly validated by comparison of atmospherically corrected image data. The results indicate that vegetation indices can be interconverted to a precision of 12%. This result offers improved opportunities for monitoring crops through the growing season and the prospects of better continuity of long-term monitoring of vegetation responses to environmental change. Numéro de notice : A2003-367 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2003.08.010 En ligne : https://doi.org/10.1016/j.rse.2003.08.010 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26447
in Remote sensing of environment > vol 88 n° 4 (30/12/2003) . - pp 412 - 422[article]Electromagnetic wave scattering from the sea surface in the presence of wind wave patterns / V. Shrira in International Journal of Remote Sensing IJRS, vol 24 n° 24 (December 2003)
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Titre : Electromagnetic wave scattering from the sea surface in the presence of wind wave patterns Type de document : Article/Communication Auteurs : V. Shrira, Auteur ; S.I. Badulin, Auteur ; A.G. Voronovich, Auteur Année de publication : 2003 Article en page(s) : pp 5075 - 5093 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse harmonique
[Termes IGN] formule de Stokes
[Termes IGN] géophysique externe
[Termes IGN] interférence
[Termes IGN] mer
[Termes IGN] onde électromagnétique
[Termes IGN] surface de la mer
[Termes IGN] ventRésumé : (Auteur) The study is concerned with electromagnetic wave (EM) scattering by a random sea surface in the presence of coherent wave patterns. The coherent patterns are understood in a broad sense as the existence of certain dynamical coupling between linear Fourier components of the water wave field. We show that the presence of weakly nonlinear wave patterns can significantly change the EM scattering compared to the case of a completely random wave field. Generalizing the Random Phase Approximation (RPA) we suggest a new paradigm for EM scattering by a random sea surface.
The specific analysis carried out in the paper synthesizes the small perturbation method for EM scattering and a weakly nonlinear approach for wind wave dynamics. By investigating, in detail, two examples of a random sea surface composed of either Stokes waves or horse-shoe ('crescent-shaped') patterns the mechanism of the pattern effect on scattering is revealed. Each Fourier harmonic of the scattered EM field is found to be a sum of contributions due to different combinations of wave field harmonics. Among these 'partial scatterings' there are phase-dependent ones and, therefore, the intensity of the resulting EM harmonic is sensitive to the phase relations between the wind wave harmonics. The effect can be interpreted as interference of partial scatterings due to the coexistence of several phase-related periodic scattering grids. A straightforward generalization of these results enables us to obtain, for a given wind wave field and an incident EM field, an a priori estimate of whether the effects due to the patterns are significant and the commonly used RPA is inapplicable. When the RPA is inapplicable, we suggest its natural generalization by re-defining the statistical ensemble for water surface. First, EM scattering by an 'elementary' constituent pattern should be considered. Each such scattering is affected by the interference because the harmonics comprising the pattern are dynamically linked. Then, ensemble averaging, which takes into account the distribution of the pattern parameters (based on the assumption that the phases between the patterns are random), should be carried out. It is shown that, generally, this interference does not vanish for any statistical ensemble due to dynamical coupling between water wave harmonics. The suggest RPA genralization takes into account weak non-Gaussianity of water wave field in contrast to the traditional RPA which ignores it.Numéro de notice : A2003-339 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000095907 En ligne : https://doi.org/10.1080/0143116031000095907 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22634
in International Journal of Remote Sensing IJRS > vol 24 n° 24 (December 2003) . - pp 5075 - 5093[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-03241 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Geometric processing of hyperspectral image data acquired by VIFIS on board light aircraft / Y. Gu in International Journal of Remote Sensing IJRS, vol 24 n° 23 (December 2003)
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Titre : Geometric processing of hyperspectral image data acquired by VIFIS on board light aircraft Type de document : Article/Communication Auteurs : Y. Gu, Auteur ; J.M. Anderson, Auteur Année de publication : 2003 Article en page(s) : pp 4681 - 4698 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] capteur en peigne
[Termes IGN] correction géométrique
[Termes IGN] image aérienne
[Termes IGN] image hyperspectrale
[Termes IGN] longueur d'onde
[Termes IGN] spectromètre imageur
[Termes IGN] Variable-Interference-Filter Imaging SpectrometerRésumé : (Auteur) The Variable-Interference-Filter Imaging Spectrometer (VIFIS) is an airborne imaging system. Unlike usual airborne spectrometers, the image acquisition of VIFIS is based on 2D sensors with its pixel spatially registered to different passing wavelengths. The correction of perturbations upon the VIFIS platform, required by the hyperspectral image generation, relies solely on the information extracted from the 2D pushbroom image flow. In this paper, we present an analysis of the distortions of the pushbroom scan caused by perturbations upon the platform. Hyperspectral image generation algorithms and band registration methods are also discussed. A practical pre-processing approach is developed to automatically track the displacements and generate up to 64 hyperspectral bands. Finally, a preprocessing example is presented as a demonstration of the overall methodology. Numéro de notice : A2003-312 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000084305 En ligne : https://doi.org/10.1080/0143116031000084305 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22608
in International Journal of Remote Sensing IJRS > vol 24 n° 23 (December 2003) . - pp 4681 - 4698[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-03231 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Training a neural network with a canopy reflectance model to estimate crop leaf area index / F. Mark Danson in International Journal of Remote Sensing IJRS, vol 24 n° 23 (December 2003)
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Titre : Training a neural network with a canopy reflectance model to estimate crop leaf area index Type de document : Article/Communication Auteurs : F. Mark Danson, Auteur ; C.S. Rowland, Auteur Année de publication : 2003 Article en page(s) : pp 4891 - 4905 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] betterave sucrière
[Termes IGN] classification par réseau neuronal
[Termes IGN] indice de végétation
[Termes IGN] Leaf Area Index
[Termes IGN] neurone artificiel
[Termes IGN] réflectance végétaleRésumé : (Auteur) This paper outlines the strategies available for estimating the biophysical properties of crop canopies from remotely sensed data. Spectral reflectance and biophysical data were obtained over 132 plots of sugar beet (Beta vulgaris L.) and in the first part of the paper the strength of the relationships between vegetation indices (VI) and leaf area index (LAI) are examined. In the second part, an approach is tested in which a canopy reflectance model is used to generate simulated spectra for a wide range of biophysical conditions and these data are used to train an artificial neural network (ANN). The advantage of the second approach is that a priori knowledge of the measurement conditions including soil reflectance, canopy architecture and solar position can be included explicitly in the modelling. The results show that the estimation of sugar beet LAI using a trained neural network is more reliable than the use of VI and has the potential to replace the use of VI for operational applications. The use of a priori data on the variation in soil spectral reflectance gave rise to a small increase in LAI estimation accuracy. Numéro de notice : A2003-315 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000070319 En ligne : https://doi.org/10.1080/0143116031000070319 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22611
in International Journal of Remote Sensing IJRS > vol 24 n° 23 (December 2003) . - pp 4891 - 4905[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-03231 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Combining metric aerial photography and near-infrared videography to define within-field soil sampling frameworks / G.G. Wright in Geocarto international, vol 18 n° 4 (December 2003 - February 2004)
PermalinkEvent-driven SAR data acquisition in urban areas using GIS / Uwe Sörgel in GIS Geo-Informations-Systeme, vol 2003 n° 12 (Dezember 2003)
PermalinkFast SAR image restoration, segmentation, and detection of high-reflectance regions / E. Bratsolis in IEEE Transactions on geoscience and remote sensing, vol 41 n° 12 (December 2003)
PermalinkHigh spatial resolution spectral mixture analysis of urban reflectance / C. Small in Remote sensing of environment, vol 88 n° 1 (30/11/2003)
PermalinkRadiometric characterization of Ikonos multispectral imagery / M. Pagnutti in Remote sensing of environment, vol 88 n° 1 (30/11/2003)
PermalinkSpectral enhancement of selected pixels in Thematic Mapper images of the Guanajuato district (Mexico) to identify hydrothermally altered rocks / M.A. Torres-Verra in International Journal of Remote Sensing IJRS, vol 24 n° 22 (November 2003)
PermalinkUsefulness of spectral reflectance indices as durum wheat yield predictors under contrasting Mediterranean conditions / C. Royo in International Journal of Remote Sensing IJRS, vol 24 n° 22 (November 2003)
PermalinkThe coregistration, calibration, and interpretation of multiseason JERS-1 SAR data over South America / Paul Siqueira in Remote sensing of environment, vol 87 n° 4 (15/11/2003)
PermalinkSpectral reflectance characterization of shallow lakes from the Brazilian pantanal wetlands with field and airborne hyperspectral data / L.S. Galvao in International Journal of Remote Sensing IJRS, vol 24 n° 21 (November 2003)
PermalinkFully polarimetric airborne SAR and ERS SAR observations of snow: implications for selection of Envisat ASAR modes / T. Guneriussen in International Journal of Remote Sensing IJRS, vol 24 n° 19 (October 2003)
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